Does anyone know of a good way to detect when the user has built an MPI application with mpicc from implementation A and tries to launch with mpirun/mpiexec from implementation B? I know that inside of the application, I can use either MPI_Get_library_version or preprocessor info to know what implementation I am using. But can I discover anything about mpirun inside of the application? Is there anything in the environment that I can query to know if my PM is Hydra, for example? If not, can that be added? This is a relatively common user error that leads to very bad things in some cases so it would be nice to be able to detect it and throw a warning/error. Thanks, Jeff -- Jeff Hammond [email protected]